Process for the manufacture of regenerated cellulose ribbons



P 1944- T. F. BANIGAN EI'AL 2,358,376

PROCESS FOR THE MANUFACTURE OF REGENERATED CELLULOSE RIBBONS Filed NOV. 1, 1941 Pme/Hmr/o/v comm/1750 SIIEET #540 ROLL a 5m TIONA/ZY G .s /mpm am DR/ViN CIIZCUMR KNIFE .2 Ll

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BY 2k ATTORNEY Patented Sept. 19, 1944 PROCESS FOR THE MANUFACTURE OF REGENERATED CELLULOSE RIBBONS Thomas F. Banigan, Kenmore, and Roy E. Hartman, Buffalo, N. Y., assignors to E. I. du Pont de Nemours a Company, Wilmington, Del., a corporation of Delaware Application November 1, 1941, Serial No. 417,581

2 Claims. (Cl. Lil-47.5)

This invention relates to a process of manufacturing shrinkable, non-fibrous, secondary closure devices, especially regenerated cellulose and like ribbons adapted upon shrinking to tightly fit over and satisfactorily seal the primary closure to a bottle, or the like.

Shrinkable, non-fibrous, secondary closure bands for bottles have been known and used for years. They provide an attractive decoration to the container, a deterrent against tampering with the contents thereof, and facilitate compliance with the law whichrequires that a part of the government revenue stamp remain on the bottle of alcoholic beverages until the contents have been dispensed. An extensively used type of band is that having opaque and clear sections. The opaque sections, being suitably-pigmerited, provide an attractive background for printed matter (advertising, directions for opening, etc), and the clear sections, when suitably positioned, permit observation of the revenue stamp without removal of the secondary closure. U. S. A. Patents 1,647,489 (Webster), 2,121,042 (Morgan) and 2,161,561 (Dalton) are representative of the art treated in the foregoing rsum. The conventional details of band manufacture are disclosed in the foregoing U. S. .A. patents and 2,141,776 (Vautier & Fays), and since the processing of these articles is analogous to that employed with cellulosic sheet (see U. S. A. Patents 1,548,864, 1,601,289 and 2,123,883), reference could be discovered for use at least until evaluation of the market has become possible.

When continuous lengths of regenerated cellulose sheet are prepared in the conventional manner, the edges are quite irregular, and there is an undesirable thickening of the marginal portion. It is necessary to remove this thickened bead and adjacent portion of the film in order to provide a regular edge on the material to be offered to the trade. This wastage is not an insurmountable difliculty when wide sheets (four or five feet in width) are being manufactured, because of the percentage or relative proportion of the scrap to the good material, but in a ,It has now been found that existing apparatus" can be used, beaded and irregular edge formation avoided, and a very satisfactory ribbon secondary material produced, by extruding viscose in the manner heretofore employed in the prep aration of regenerated cellulose tube, and siltting the tube after coagulation and during regeneration but before the conventional purifying processing takes place.

How the foregoing objects and related ends are accomplished will be apparent from the following exposition, in which are disclosed the principle and divers embodiments of the invention, including the best mode contemplated for carrying out the same. Parts are given by weight throughout the specification unless otherwise specified. The written description is amplified by the accompanying drawing. in which:

Figure 1 is a diagrammatic side elevation view, partly in section, with some of the parts exaggerated in the interest of clarity, of the tube slitting arrangement of the present invention;

Figure '2 is an elevation view corresponding to the upper part of Figure 1, taken at right angles to the view of Figure l; and

Figure 3 is a fragmentary conventionalized perspective view, with parts exaggerated for clearness, of the cutting device.

Example A cellulosic tube having 4 longitudinal sections alternately clear and pigmented was prepared by extruding viscose in the manner set out in U. S. A. Patent No. 2,141,776. The viscose contained 7% cellulose and 6% sodium hydroxide. The viscose used in the opaque sections contained, in addition, 1% titanium dioxide (based on the weight of the viscose). The viscose was extruded upwardly into an aqueous bath containing 15% sulfuric acid and 16% sodium sulfate.

The continuous tubing passed at the rate of approximately feet per minute through 72 inches of this coagulating bath. After emerging from the bath and travelingapproximately 2.0 feet, the tube was slit by a cutting device comprising a straight knife blade operating in con- Junction with a circular sharpened disc which rotated against the blade. A stream of air directed into the open tubing just above the slitter kept the tube dilated and free from creases. The slit tube was then passed under a spreader rod and over a roll to open the tube andfiatten the resulting web, after which it was passed into a regenerating bath. A negligible amount of retion. This situation prevails even .when the coagulation bath has a high acid content, because the tubing is not in contact with the coagulating solution for a sufficiently long time to appreciably regenerate the cellulose. bath the time of treatment and strength of acid are correlated to finish the regeneration.

The regenerated band was then conducted through a series of treatment vats for desulfuring, bleaching, etc., in the conventional .manner for processing regenerated cellulose.

At the time of slitting, the tube had a perimeter of approximately 130 millimeters and a thickness of 0.014 inch. After processing, the web was 104 millimeters wide and had a thickness of 0.010

In the regeneration generation took place before the slitting opera- Printing 'wasthen applied to the opaque sections in the customary manner (see U. S. A. Patent No. 1,997,769 to Fletcher).

ous alkali soluble lowsubstituted cellulose 'ethers (see U. S. A. Patents 2,234,016 to Woodhouse-and 2,123,883 to Ellsworth) manufacturing procedures.

The products of this invention may be colored in any desired manner, for example, by pigmenting the viscose ordyeing the shaped product.

Other types of ornamentation or decoration for such products are well known in the art and may be employed, or if desired, the entire tube and resulting ribbon may be clear and transparent.

In order to give uniform tubing, it is desirable that the walls of the extrusion orifice be concentric circles. A slight variation into an elliptical form may be employed so long as the clearance of the two walls is uniform and the eccentricity of the ellipse is not so great as to unduly These advantages types. One uses stacked individual strips, and the upon which it was placed. The dried article had good durability and practically uniform physical properties across its width. The transparency of the clear sections was very satisfactory.

The lengthwise slitting of the tube may take place before, during or after regeneration. Be-

cause of difficulties in processing tubing satisfactorily, it is preferred to slit the tubing before it passesthe first support after leaving the coagulating bath. In this mode of operation the web is formed after the gel body has lost its ability to form a beaded edge, and the process is distort the web when flattened. Various slittingdevices may be employed in opening up the tubing. Good results can be obtained with rotary shears, vibrating shears, etc., but the combination knife and disc has been found especially satisfactory.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

We claim:

1. In the production of a regenerated cellulose ribbon, the steps comprising continuously extruding .viscose in the form of a tube, continuously coagulating the tube in a coagulating bath, continuously withdrawing the coagul'ated tube from the coagulating bath, dilating the coagulated tube with an air jet as it passes from said coagulating bath, slitting the tube longitudinally while it is dilated by said air jet whereby to form a ribbon, and passing said ribbon into a regenerating bath to complete the regeneration thereof.

2. In the production of a regenerated cellulose ribbon, the steps comprising continuously extruding viscose in the form of a tube, continuously coagulating the tube in a coagulating bath, continuously withdrawing the coagulated tube from the coagulating bath, dilating the coagulated tube with an air jet as it passes from said coagulating bath, slitting the tube longitudinally approximately 2 feet from said coagulating bath while it is dilated by said air jet whereby to form a ribbon, and passing said ribbon into a regenerating bath to complete the regeneration thereof.

THOMAS F. BANIGAN. ROY E. HAR'IMAN. 

